Device for use in teaching geometry or trigonometry



Patented'lune 9, 1925.

UNITED STATES GEORGE A. PAR-KINSON, F MADISON, WISCONSIN.

DEVICE FOR USE IN TEACHING GEOMETRY OR TRIGONOMETRY.

Application filed A ril 17, 1924. Serial No. 707,086.

To all whom it may concern:

Be it known that I, GEORGE A. PARKIN- soN, a citizen of the UnitedStates, residing at Madison, in the county of Dane and 6 State ofWisconsin, have invented a certain new and useful Improvement in Devicesfor Use in- Teaching Geometry or Trigonometry, of which the following isa specification.

It is frequently the case with the youthful mind that it is lacking inthe necessary imaginative power to grasp the significance of mere drawnlines and their proposed superposition upon each other especially, for

example, as where equal angles or equal triangles are to be proved such.Minds of this kind can often be helped if such lines, angles &c. berepresented in tangible form. Hence it is the object of the presentinvention to provide an apparatus whereby lines, angles &-c. of varioussorts are represented in concrete form and the parts of the apparatusmanipulated to illustrate many of the elementary geometrical andtrigonometrical terms and processes employed in making the proofsnecessary in 'those branches of mathematical science.

The invention is embodied in the example herein shown and described, thefeatures of novelty being finally claimed.

In the accompanying drawing- Figure 1 is a plan view of several parts ofmy apparatus connected together in a manner adapted to illustrate manyof the terms of geometry and trigonometry.

Fig. 2 shows the main frame which is hinged to fold on two axes spreadout in edge view.

Fig. 3 shows the same frame folded on one of its axes.

Fig. 4 illustrates a bar to be applied to the frame and,

Figs. 5, 6 and 7 arcuate pieces of 30, 45, and 60 degrees respectivelythat may also be applied to the main frame.

Fig. 8 is a cross section of one of the right angle arms at a slottherein showing a clamping device applied thereto.

Fig. 9 is a detail view of a suspending means for the frame.

The main frame is composed of four right angled pieces 10 convenientlyof equal size and of like shape joined together in the form of a crossby hinges at 11 and 12 so that, for example, the left hand pair can bero- 55 tated on the hinges 11 to lie on the right hand pair with theangles of the pairs coinciding; or, for example, so that the lower paircan be rotated on the axis of the hinges 12 to lie over the upper pairwith the angles of those pairs coinciding. In Fig. 9 is illustrated adevice at 20 wherebythe frame may be conveniently hung on a nail onawall or board. Said device consists of two leaves hinged together, oneof said leaves having an eyelet extension, the eye of which, as wellasthe axis of the hinge of the leaves referred to, lies in linewith theaxis of the hinge at 11. This hanging device can be added if desired, bywelding or otherwise securing it to the arms 10 of Fig. 1 and asillustrated in Fig. 9. When spread out flat on a table or hung upon awall as by means of the hinged eyelet 20 at the vertical axis of theframe it is to be viewed as representing one straight line intersectinganother at right angles and forming four right angles. In this positionalso it represents the axis of abscissas and ordinates or the entireangular magnitude about the origin of coordinates. In the constructionshown the bar of each of the angle pieces can be formed of sheet metalor other suitable material l 'lshape'in cross section and provided witha slot 14 so as to receive at its hollow or groove side asquare nut 15 kprovided with a. fixed screw 16 that projects through the slot andreceives a milled nut 17 whereby another member such as a rod Fig. 4 oran are as in Figs. 5, 6 or 7 can be fixed to the angle piece. The squarenut can be slid along the groove in which it is located and because itfits it is held from turning when the milled nut 17 is turned to clampthe parts together. The rod and the arcs are each shown as provided witha series of perforations such as seen at 18 through any of which thescrew of the clamping means can be passed to secure it in position. Aperforation at 19 near the corners of each of the angle bars permits theattachment of a rod to illustrate angles greater or less than a rightangle.

In Fig. 1 is illustrated some of the many ways in which rods and arcscan be applied to the frame and it will be observed by those familiarwith mathematics that as shown in this view there are illustratedtangents, a square, several triangles, a trapezium, sectors, sines,cosines, abscissa-s, ordinates, and other features. In the practical useof the device it would not be necesszuiy or ierhaps desirable, to applyat one time as many of the members as are shown applied in Fig. 1 butonly that or those required in a singie illustration or demonstration.By means of the perforations in the bars their position can be changedor they can be shifted to change the angular magnitudes and the forms clany of the figures to be represented as may be desired or deemedadvantageous by the instructor using the apparatus. The lamping of anapplied member at one point will usually sufiice for practical purp secit the equality of two angles or trianig similarity o't is to be shou iperposition the appropriate rods connected in symmetrical or similararrangement to adjoining right a H ed pieces and these folded together.It ti o difference between two given angles or figures is to be shownthis can likewis demonstrated by superposition.

ihe device can be manu' *tured out of thin strips of sheet metal andmore oi the parts than show; and in diiierent forms or s'izescan befurnished with a set For example arcuate pieces cut on d f" mnt radiican be added.

The forms oi? th without departing vention as claimed.

What I claim is:

l. An apparatus adapted for use in ing geometry or trigonon'ietrycompiframe composed of angle members hi1 their sides to each other topermit coinciding superiiiosition, one oi said angle members providedwith a slot, a bar and means for aojustably securing said in said s ot,

2. An apparatus adapted if 'i' use in teaclu ing geometry ortrigonometry comprising a frame con'iposed of four angle members hingedat their sidesto each other on two axes to permit coincidingsuperposition by rotation of pairs of the members on either of suchaxes. V

3. An apparatus adapted for use in (earliing geometry or trigonometrycom irising a frame composed of four right angle members hinged togetherat .their sides on two axes to permit coinciding superposition byrotation of the members on either of such axes.

41-. An apparatus adapted for use in teaching geometry ortlIll'OllOITlQtlY comprising a 5 Irame composed 0i angle men'ibershinged at their sides to each other to permit coinciding superpositionand straight and arruate rods with means for securing them to one ofsaid members.

An apparatus adapted for use in teachin geometry or trigonometry comprframe composed of angle members hing ed their sides to each other topermit coincidi115 superposition and straight and arcuate rods withmeans tor adjustably securing" them to one of said members.

6. tin api )aratiis adapted for use in teach ing geometry ortrigonometry comprising): i rame composed of angle members hingeotogether at paralieily arrange sides to pen mit ='=oincidingsuperposition and a h device for said frame consisting of a h l to saidlelly arranged angular members and eye-bearing; member attachesubstantially with th line ot the axis of hinges ot' the i i devices.

7. 13.11 apparatus adapted for use in teaching geometry or mometry'comprising a frame composed of right angle members hinged together onlines at right angles to each other to representthe axes of abscissasand ordinates when exteude, said angled members adapted to 'iOltlQCl oneither axis of hinging.

GEORGE A. PARKINSUN.

